The above prior patent application discloses a fuel atomizing valve for engines which are supplied with fuel and air through a carburetor whose primary function is to establish and maintain a proper air-fuel mixture ratio. In the prior application, the variable atomizing valve is supported on a mounting module arranged between the base of the carburetor and the customary carburetor mounting pad of the intake manifold. The valve projects through the main inlet opening of the manifold and into the manifold passage leading to the cylinders of the engine. The valve consists of a stationary sleeve surrounded by a coaxial telescoping relatively movable atomizing screen assembly which includes a rigid screen cage which holds and confines a pair of closely interfitting coaxial cylindrical screens, the interior one of which is of relatively coarse mesh, the outer screen being of much finer mesh construction. Guide bearing means provided between the screen assembly and the fixed sleeve establish an essential radial jump space across which the inducted air-fuel mixture is accelerated at the outlet end of the fixed sleeve in response to engine-created suction before impinging upon the atomizing screens. The movable screen assembly is yieldingly biased toward a nearly closed slow idle position relative to the fixed sleeve but extends itself automaticaly against the biasing means in response to engine demand to provide an infinitely variable atomized fuel delivery device directly into the intake manifold for all conditions of engine operation and demand.
While the atomizing valve according to the prior application operates with good efficiency to atomize fuel to a degree heretofore unattainable in the prior art and to deliver a homogeneous mixture of air and fuel into the intake manifold on demand, nevertheless, certain variables inherently present in piston engines exceeds the capability of the atomizing valve to respond completely to these variables particularly in terms of instantly deliverying the required volume of air under all conditions and in assuring the necessary intimate comingling and mixing of the air with fuel immediately prior to delivering the atomized charge into the manifold passage leading to the cylinders.
In view of the above, it is the object of this invention to substantially improve the variable atomizing valve of the above patent application so that it can satisfy automatically and immediately in response to engine demand all of the varying requirements for a superatomized homogeneous cool and dense fuel charge at each cylinder of an engine in the necessary volume for optimum engine operation at all speeds and under all power requirements encountered in normal operation. In essence, the present invention reacts automatically to engine demand without external control to deliver to the several cylinders the optimum fuel charge for greatest efficiency under all conditions encountered from slow idle through high speed high load operation. At any given engine demand situation, the fuel charge will contain the optimum volume of air and the always essential homogeneous mixture of air and fuel making up the combustible charge. Furthermore, the improved value and manifold arrangement will insure high velocity delivery of the charge through the manifold passage without the possibility of separation of the atomized fuel from the air during such delivery plus equality of charge volume, density and combustible quality at each cylinder under all conditions. The improved atomizing valve requires no additional moving components. As stated, it can respond to engine demand and alter its air volumetric capacity or air flow through effective size without external control. In accomplishing this, all of the desirable features of the atomizing valve according to the prior patent application are retained, including simplicity of construction, reliability and comparative low cost of manufacturing. The invention is entirely compatible with either carburetion fuel systems or fuel injection systems of the class in which raw fuel is directly injected into the center of the intake manifold upstream from the engine cylinders. The invention is also completely compatible with various piston engine configurations including four and six cylinder in-line engines which the automobile industry is turning to in the present-day energy crisis.
The heart of the improvement in the variable atomizing valve is the provision of a second exterior fixed sleeve in concentric surrounding relationship to the inner fixed sleeve. The movable screen assembly surrounds and telescopes over the exterior fixed sleeve and responds to engine demand generally in the manner set forth in the prior application.
A very important benefit derived from the use of the second exterior fixed sleeve is a substantial increase in the radial jump space for air and fuel as the latter change direction at the outlet ends of the fixed sleeves and begin to enter the main manifold passage after impinging upon and passing through the atomizing screens. This jump space in the improved valve is the full distance between the periphery of the interior fixed sleeve and the annular screen structure through which the accelerating fuel charge must pass to become superatomized. Because of the larger jump space, the velocity of the mixture impinging on the screen is supersonic, and this results in atomization of the fuel into particles of near molecular size with the atomized particles remaining at all times mixed with air in a homogeneous manner. In this important way, the results achieved with the invention are dramatically different from the prior art fuel delivery systems where unatomized fuel droplets are entrained in air entering conventional intake manifolds in a mixture of varying and changing density and continuity. As is well known, light vaporous fuel molecules ignite and burn readily in the engine whereas heavy molecules may fail to ignite or to burn completely, resulting in great losses of power, increased hydrocarbon pollutants in exhaust emissions and excessive carbon buildup, among many other known disadvantages.
In addition to the feature of increased jump space above discussed, the improved atomizing valve having the two concentrically spaced fixed sleeves insures complete and thorough intermixing of fuel and air into a nearly perfect homogeneous charge prior to its superatomization and in the critical zone between the carburetor or suitable injection means and points of entry into the manifold passage following passage of the mixture through the screens. In this connection, all of the supplied fuel under all engine demand conditions must enter and pass through the relatively confined passage provided by the interior sleeve, whereas air only under certain increased conditions of demand enters and passes through the annular space between the two fixed sleeves. Because of this unique arrangement there will always be proper thorough mixing of fuel and air within the bore of the inner fixed sleeve regardless of varying engine demand for a greater or lesser volume of the fuel charge. Under low demand conditions, all required air and fuel for optimum engine operation may be delivered through the interior fixed sleeve. As demand increases, some air and increasing volumes of air only are delivered through the annular space between the two fixed sleeves to satisfy engine requirements but without disturbing the mixing capability of the valve within the inner sleeve.
Another feature of the improved atomizing valve is the provision thereon of a fine conical screen across the top of the annular air only passage between the two fixed sleeves to divert or funnel all air into the interior sleeve passage for confined intermixing with fuel at low engine demand, such as idling. At such times, manifold suction is insufficient to force air through the conical screen and into the annular space between the two sleeves. However, as demand increases and suction in the manifold increases accordingly, additional air and air only will begin to be drawn through the conical screen to automatically increase the volumetric capacity of the valve, as air and fuel continue to pass without interruption through the interior sleeve. The necessary increase or decrease in fuel to meet changing conditions of demand is satisfied by state-of-the-art liquid fuel controls which, per se, are not a part of this invention.
In a second major aspect of the invention, the intake manifold of the engine is restructured to coact with the improved valve in a unique manner to satisfy engine demand most efficiently. Toward this end, the intake manifold has a divider plate between its top and bottom walls, preferably spaced from the top wall about one-third of the total distance between the two walls. The divider plate extends completely between the manifold side walls and is continuous from the main central inlet of the manifold receiving the valve to the individual cylinder fuel inlet ports. The divider plate defines two separated manifold passages, one of which is somewhat narrower than the other. Under low engine demand conditions, atomized fuel and air may be delivered by the valve into only the narrower passage with the wider passage completely blocked off. As demand increases, the second manifold passage gradually comes into play and is progressively uncovered. At maximum engine demand, both passages are active and receive the atomized charge from the valve. The arrangement insures that the atomized charge passes through the manifold at sufficient velocity and charge density and in a homogeneous state to enable optimum engine operation at all times.
Other features and advantages of the invention will become apparent to those skilled in the art during the course of the following detailed description.